Boa ConstrictorsBoas are a type of snake that are members of the Boidae family. Boas are basal snakes that are "primitive" in evolutionary terms (i.e. less derived). They are constrictors and give birth to live young.

Boas have two subfamilies: Boinae or true boas and Erycinae or sand boas. Pythons are sometimes classified as a subfamily of Boidae, but are frequently listed under their own family, Pythonidae.

[edit]BoinaeTrue boas are medium-sized to large snakes. It used to be said that boas were New World Snakes and pythons were Old World Snakes, but, with boas found on Madagascar and the Solomon Islands, this is not quite true. Instead, it is possible that boas have survived in evolutionarily isolated areas. South America, until a few million years ago, had a distinct fauna that included marsupial mammals; with the land bridge to North America, boas have migrated north as placental mammals and colubrids (for example) have migrated south.

Acrantophis (Dumeril's Boa and Madagascar Ground Boa; sometimes equated with Boa) Boa (Boa Constrictors) Candoia (Pacific Boas) Corallus (Tree Boas) Epicrates (Rainbow Boas and Island Boas) Eunectes (Anacondas) Sanzinia (Madagascar Tree Boa; sometimes equated with Boa) [edit]ErycinaeCompared to true boas, erycines are quite small, with most members of this subfamily remaining well under a metre in length. Fossil erycines have been found in rock strata over 50 million years old, and were once widespread in North America. Now, only two species remain in North America, as well as the sand boas in Africa, Asia and southeastern Europe.

At least three erycine species lay eggs: the Calabar Burrowing "Python", Calabaria reinhardtii (once classified as a python for this reason); the Arabian Sand Boa, Eryx jayakari; and the West African Sand Boa, Eryx muelleri.

Reticulated PythonWith a maximum recorded length of over 10 metres, the Reticulated Python (Python reticulatus) is the longest extant snake species. But because it is slender and elongate, it is not the largest: the Green Anaconda is roughly twice as heavy at the same length. Those who work with reticulated pythons often cite an unsual level of intelligence and awareness compared to other species.

Although their interactivity and beauty draws much attention, some feel they are unpredictable. Attacks are rare, but the species has been responsible for several human fatalities in both the wild and captivity. Reptile enthusiasts are quick to note, however, that there are far more human deaths each year caused by dogs than by large constrictors.

Inexperienced owners can enable snake escapes, causing injury to the owners themselves and people living nearby. For the health and safety of both the snake and humans, reticulated pythons should only be kept by experienced keepers equipped to handle large constrictors.

King SnakesKing snakes are a type of snake that are members of the Lampropeltis genus.

These snakes, which are part of the colubrid family, eat rodents and can get quite large.

Lampropeltis means "shiny shields" and the majority of king snakes have quite vibrant patterns on their skin. King snakes are constrictors and tend to be opportunistic when it comes to their diet; they will eat other snakes, lizards, rodents, birds, and eggs. They are highly resistant to the venom of other snakes, and have been known to eat them. The "king" in their name (as with the King cobra) is a reference to their taste for snake meat.